Terminal box for lifting magnet

ABSTRACT

A terminal box for a lifting magnet is disclosed which may be separately fabricated and then attached to the lifting magnet. The terminal box is provided with an easily removable cover which clamps an incoming power-source cable to relieve internal cableconnection stress. Removal of the cover allows access to the internal cable connections without removal of the entire terminal box. The incoming power-source cable is held locked to the internal cable by an easily removable pin which is permanently attached to the terminal box.

United States Patent [72] Inventor Jerry L. Swope Columbus, Ohio [21] AppLNo. 810,217 [22] Filed Mar. 25, 1969 145] Patented Nov. 16, 1971 [73 Assignee McGraw-Edlson Company Elgin, Ill.

[54] TERMINAL BOX FOR LlFTlNG MAGNET 11 Claims, 3 Drawing Figs.

[52] US. Cl 335/290, 174/65 R, 335/292, 336/107, 339/103 R [51] Int.Cl l-l0lf7/20 [50] Field of Search 174/50, 50.5, 52, 65, 135, 66; 335/290-292, 294; 220/38, 3.92,4, 7, 32,55; 317/99, 120; 336/96, 192, 107

[56] References Cited UNITED STATES PATENTS 1,532,449 4/1925 Sederholm 335/290 2,813,232 11/1957 Lillquist 335/291 FORElGN PATENTS 941,071 4/1956 Germany 174/65 331,307 7/1930 Great Britain 174/65 Primary Examiner-Darrell L. Clay Attorney-Richard C. Ruppin PATENTEDunv 1s 19?:

SHEET 1 OF 2 FIGI ATTORNEY TERMINAL BOX FOR LIFTING MAGNET BACKGROUND OF THE DISCLOSURE This invention relates to a terminal box and in particular to a terminal box for a lifting magnet.

Present terminal boxes for lifting magnets generally have a shape dictated by their design requirements which limits their positioning on the lifting magnet. Without such location flexibility, a single or standard design terminal box which meets the requirements of various lifting-magnet users cannot be manufactured. Another common type of terminal box for a lifting magnet is one that is cast integrally with the lifting-magnet cover and is therefore also limited to a single location on the lifting magnet. This latter type of terminal box also has the disadvantages of not being replaceable separately from the lifting-magnet cover and of being difficult to machine after casting since the entire lifting-magnet cover must be handled when it is desired to work on only the terminal box. A further problem in presently known terminal boxes is that the entire terminal box must be removed from the lifting magnet in order to gain access to internal cable connections.

It is accordingly an object of the invention to provide a terminal box for a lifting magnet which may be manufactured separately from the magnet and which may be readily attached and removed from the lifting magnet.

Another object of the invention is to provide a terminal box for a lifting magnet having a cover which may be easily removed to allow access to the terminal connection between the incoming power-source cable and the magnet cable.

Another object of the invention is to provide a terminal box for electrical apparatus having a removable cover which clamps a cable extending into the terminal box when the cover is in place on the box.

Another object of the invention is to provide a cover for a terminal box having a pin which holds the cover in place and which may be used to remove the cover from the box.

A further object of the invention is to provide a cover for a lifting-magnet terminal box having means for attaching the cover to the terminal box recessed in the walls of the terminal box.

A further object of the invention is to provide a terminal box for electrical apparatus having a pin within the box for locking an incoming electrical cable to the electrical apparatus.

These and other objects and advantages of the instant invention will be apparent from the description of the preferred embodiment hereinbelow.

SUMMARY OF THE INVENTION The objects of the invention are accomplished by providing a terminal box for a lifting magnet which may be fabricated separately from the lifting magnet. The terminal box has a cover held in place on the box by a tongue-and-pin arrangement allowing easy removal of the cover from the box so that access to the power'source cable and magnet cable may be attained without removing the entire terminal box from the magnet. The cover clamps the incoming power-source cable to the box when the cover is in place and the power-source cable is also locked to the lifting magnet by a locking pin within the terminal box. The locking pin also locks the magnet cable and the power-source cable together. The pin holding the cover on the terminal box may also be used to remove the cover from the box.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of the terminal box of the invention;

FIG. 2 is an end elevational view of the terminal box positioned on a lifting magnet; and

FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2 showing the cable connection within the terminal box.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring generally to the drawings, a terminal box 4 having a cover 6 is shown attached by suitable means such as welding to a lifting magnet 2. A supply cable 8 connected to an electrical power source (not shown) and having conductors l0 and 12 covered by insulation material 14 is brought into the terminal box 4 and connected to external lead 16. The external lead 16 is connected to the internal lead 18 by plug members 20 which comprise part of the internal lead 18. The internal lead 18 is mounted on the wall 22 of box 4 and provides a watertight seal between the interior and exterior of the lifting magnet 2. An internal lead cable 24 extends from the lead 18 and is connected to the lifting magnet cable 26 by connector 28. The cable 26 is connected to a magnet winding (not shown) within the lifting magnet 2. It may be noted that, except for the provision for locking the external lead 16 and the internal lead 18 together, the external lead 16, internal lead 18 and connector .28 are all standard components and well known in the art and therefore will not be discussed in detail.

The terminal box 4 includes a cable-locking means having a securing bracket 30 and a locking pin 32 permanently secured to the bracket 30 by means of chain 34. A lead protector 36 is affixed to the wall 4 by screws 37 and is provided with a pinhole 38 which is aligned with a pinhole 40 in the external lead 16 when the external lead 16 is connected to the internal lead 18. The locking pin 32 is removably inserted into the pinholes 38 and 40 when the external lead 16 and internal lead 18 are connected together so that the external lead 16 and internal lead 18 are locked together and the supply cable 8 is locked to the lifting magnet 2. The locking pin 32 is prevented from moving out of the pinholes 38 and 40 by the cover 6 when it is in place on the terminal box 4 (see FIG. 3).

As may be seen in FIGS. 1 and 2, the terminal box 4 has three external sidewalls designated by the numerals 42, 44 and 46. The sidewall 42 has a slot 56 extending across a portion of its width and the sidewall 44 has an opening 48 extending therethrough and including a recessed portion 50. Directly opposite the opening 48, the sidewall 46 has an external groove 52 extending a portion of the height of wall 46 and an opening 54 extending through the wall 46 into the groove 52. As may be best seen in FIGS. 1 and 3, the cover 6 has a tab 58 which extends into the slot '56 when the cover 6 is in place as shown in FIG. 3. The cover 6 includes an internally extending portion 60 having an opening 62 therethrough which is aligned with the openings 48 and 54 in walls 44 and 46 when the cover 6 is in place on the box 4. The cover 6 is held in place on the terminal box 4 by the locking action of the tab 58 in the slot 56 and a pin 64 which extends through the openings 48 and 54 in the walls 44 and 46 and the opening 62 in the cover portion 60. The cover pin 64 has an opening 66 and is held in place by suitable means such as cotter pin 68. When the pin 64 is in place on the terminal box 4, its opposite ends are recessed within the groove 52 and recessed portion 50 so that maximum protection against mechanical wear is afforded.

The cover 6 has a cable entrance slot 70 having a height less than the diameter of the power-source cable 8 so that when the cover 6 is in place, the slot 70 clamps the cable 8 tightly to the terminal box 4. In this manner, a major portion of the stress on the internal cable connection is avoided to prevent the supply cable 8 from pulling loose from the lifting magnet 2.

The cover 6 also includes an opening 72 in its end adjacent the cable 8. The opening 72 extends into the portion 60 of cover 6 and connects with the opening 62. The opening 72 has a diameter of sufficient size to accept the pin 64 so that the pin 64 can be utilized to loosen and remove the cover 6. This feature of the invention is particularly useful when the cover 6 has been in place for a long period of time and corrosion and dirt have caused it to become jammed on the box 4.

As shown in FIGS. 1 and 3, the terminal box 4 includes a terminal cover wall 76 having a terminal access opening 82 allowing access to the connector 28 which connects the internal lead cable 24 and the lifting-magnet cable 26. A terminal cover 74 and a gasket 80 are held in place on the cover wall 76 by screws 78. The gasket 80 is provided to insure watertightness of the internal cable connection. Since the cover 74 is removable, access to disconnect cables 24 and 26 at connector 28 permits removal of the entire terminal box 4 as a unit including the internal lead 18 and lead protector 36.

While only a single embodiment of the invention has been shown herein, it will be realized that many modifications thereof are feasible without departing from the spirit and scope of the invention. It is consequently intended in the appended claims to cover all such variations and modifications as fall within the true spirit and scope of the invention.

lclaim:

1. In a lifting magnet connected to a power source and including a winding and a terminal box, the combination comprising, a supply cable connected to said power source and extending into said terminal box, a magnet cable connected to said winding and extending from the interior of the lifting magnet into said terminal box, said magnet cable being connected to said supply cable within said terminal box, said terminal box having a removable cover and sealing means separate from said cover within said terminal box for providing a watertight seal between the interior and exterior of the lifting magnet, the connection of said supply and magnet cables being accessible exterior said terminal box when said cover and sealing means are removed, and locking means including an elongated member having a position extending into said supply cable and held in said position by said cover whereby said supply cable is held within said terminal box.

2. The combination according to claim 1 wherein said locking means includes a hollow member affixed to said lifting magnet, said supply cable extending into the hollow member and said elongated member extending into said hollow member and the supply cable transverse of the length of the supply cable.

3. The combination according to claim 2 wherein said hollow member comprises a tube affixed to said terminal box and said elongated member comprises a pin.

4. In combination with a lifting magnet including a winding electrically connected to a power source, the combination comprising, a terminal box mounted on said magnet and including an open side and a cover enclosing said open side, said cover having an opening contiguous to and extending in a direction away from an edge of said side, said opening having a predetermined dimension in said extending direction, and a supply cable connected to said power source and said winding and projecting through said opening to the terminal box, said cable having a diameter greater than said predetermined dimension whereby said cable is clamped between the opening of the cover and the edge of the terminal box when the cover is closed.

5. The combination according to claim 4 further comprising locking means including an elongated member having a position extending into said supply cable and held in said position by said cover whereby said supply cable is held within said terminal box.

6. The combination according to claim 5 wherein said terminal box includes first and second spaced-apart sidewalls and a third sidewall connecting said first and second sidewalls, a removable cover enclosing said terminal box, said cover being positioned between said first and second sidewalls and having an end engaging said third sidewall, said end projecting into said third sidewall, and a removable cover pin extending through said first and second sidewalls and said cover whereby said cover is held closed.

7. The combination according to claim 4 wherein said cover is movable in a direction toward and transverse to the length of said cable.

8. in combination with a lifting magnet, a terminal box mounted on the lifting magnet and having first and second spaced-apart sidewalls and a third sidewall connecting said irst and second sidewalls, a removable cover enclosing said terminal box, said cover being positioned between said first and second sidewalls and having an end engaging said third sidewall, said end projecting into said third sidewall, and a removable cover pin extending through said first and second sidewalls and said cover whereby said cover is held closed.

9. The combination according to claim 8 wherein said third sidewall has a slot formed therein and the end of said cover has a tab projecting into said slot.

10. The combination according to claim 8 wherein said first and second walls each have a recess positioned on their outer surfaces coaxially with said cover pin and said cover pin has two opposed ends such each positioned within one of said recesses.

11.,The combination according to claim 8 wherein said cover has a removal opening spaced from said end, said removal opening having a surface positioned to allow application of force to said cover in the direction of the height of the walls of the terminal box, said removal opening having crosssectional dimensions larger than the diameter of said cover pin whereby said pin may be inserted into said removal opening and utilized to apply force in said direction to remove the cover. 

1. In a lifting magnet connected to a power source and including a winding and a terminal box, the combination comprising, a supply cable connected to said power source and extending into said terminal box, a magnet cable connected to said winding and extending from the interior of the lifting magnet into said terminal box, said magnet cable being connected to said supply cable within said terminal box, said terminal box having a removable cover and sealing means separate from said cover within said terminal box for providing a watertight seal between the interior and exterior of the lifting magnet, the connection of said supply and magnet cables being accessible exterior said terminal box when said cover and sealing means are removed, and locking means including an elongated member having a position extending into said supply cable and held in said position by said cover whereby said supply cable is held within said terminal box.
 2. The combination according to claim 1 wherein said locking means includes a hollow member affixed to said lifting magnet, said supply cable extending into the hollow member and said elongated member extending into said hollow member and the supply cable transverse of the length of the supply cable.
 3. The combination according to claim 2 wherein said hollow member comprises a tube affixed to said terminal box and said elongated member comprises a pin.
 4. In combination with a lifting magnet including a winding electrically connected to a power source, the combination comprising, a terminal box mounted on said magnet and including an open side and a cover enclosing said open side, said cover having an opening contiguous to and extending in a direction away from an edge of said side, said opening having a predetermined dimension in said extending direction, and a supply cable connected to said power source and said winding and projecting through said opening to the terminal box, said cable having a diameter greater than said predetermined dimension whereby said cable is clamped between the opening of the cover and the edge of the terminal box when the cover is closed.
 5. The combination accOrding to claim 4 further comprising locking means including an elongated member having a position extending into said supply cable and held in said position by said cover whereby said supply cable is held within said terminal box.
 6. The combination according to claim 5 wherein said terminal box includes first and second spaced-apart sidewalls and a third sidewall connecting said first and second sidewalls, a removable cover enclosing said terminal box, said cover being positioned between said first and second sidewalls and having an end engaging said third sidewall, said end projecting into said third sidewall, and a removable cover pin extending through said first and second sidewalls and said cover whereby said cover is held closed.
 7. The combination according to claim 4 wherein said cover is movable in a direction toward and transverse to the length of said cable.
 8. In combination with a lifting magnet, a terminal box mounted on the lifting magnet and having first and second spaced-apart sideWalls and a third sidewall connecting said first and second sidewalls, a removable cover enclosing said terminal box, said cover being positioned between said first and second sidewalls and having an end engaging said third sidewall, said end projecting into said third sidewall, and a removable cover pin extending through said first and second sidewalls and said cover whereby said cover is held closed.
 9. The combination according to claim 8 wherein said third sidewall has a slot formed therein and the end of said cover has a tab projecting into said slot.
 10. The combination according to claim 8 wherein said first and second walls each have a recess positioned on their outer surfaces coaxially with said cover pin and said cover pin has two opposed ends such each positioned within one of said recesses.
 11. The combination according to claim 8 wherein said cover has a removal opening spaced from said end, said removal opening having a surface positioned to allow application of force to said cover in the direction of the height of the walls of the terminal box, said removal opening having cross-sectional dimensions larger than the diameter of said cover pin whereby said pin may be inserted into said removal opening and utilized to apply force in said direction to remove the cover. 